Treatment of respiratory disorders, such as obstructive sleep apnea (OSA), with a continuous positive airway pressure (CPAP) flow generator system or treatments of respiratory insufficiency with a ventilator flow generator system, typically involve a delivery of air (or other breathable gas) at pressures above atmospheric pressure to the airways of a patient via a conduit and/or a respiratory mask. Typically, the mask fits over the mouth and/or nose of the patient, or may be an under-nose style mask such as a nasal pillows or nasal cushion style mask.
The associated respiratory treatment systems typically include a flow generator, an air filter, a respiratory mask or cannula, an air delivery conduit connecting the flow generator to the mask, one or more sensors and a microprocessor-based controller. The flow generator may include a servo-controlled motor and an impeller. The flow generator may also include a valve capable of discharging air to atmosphere as a means for altering the pressure delivered to the patient as an alternative to motor speed control. The sensors may measure, amongst other things, motor speed, gas volumetric flow rate and outlet pressure, such as with a pressure transducer, flow sensor or the like. The apparatus may optionally include a humidifier and/or heater elements in the path of the air delivery circuit. The controller may include data storage capacity with or without integrated data retrieval/transfer and display functions.
For a patient receiving a pressurized respiratory treatment from such a flow generator, such as a CPAP treatment, bi-level pressure treatment, a pressure support ventilation treatment, etc., and wearing a mask, speaking can be difficult. A non-interrupted gas from the flow generator that enters a patient's mouth and lungs can impede vocalization. In such situations, a patient must either remove his/her mask or turn the flow generator off.
It may be desirable to develop further apparatus to improve patient comfort or convenience when using a respiratory treatment system.